(a) Field of the Invention
The present invention relates to a thin film transistor array panel and a display device.
(b) Description of the Related Art
Liquid crystal displays (“LCDs”), which are one type of flat panel display devices, include two panels, one with pixel electrodes formed thereon and one with a common electrode formed thereon, and a liquid crystal layer with dielectric anisotropy interposed between the two panels. The pixel electrodes are arranged substantially in a matrix and are connected with switching elements such as thin film transistors (“TFTs”) to receive an image data voltage sequentially row by row. The area formed by each pixel electrode is referred to as a pixel, and an LCD may include a plurality of pixels. The common electrode is formed on the entire surface of one of two panels and receives a common voltage. A pixel electrode, the corresponding portion of the common electrode, and corresponding portion of the liquid crystal layer interposed therebetween form a liquid crystal capacitor in terms of circuitry, and the liquid crystal capacitor is a basic element of a pixel together with the switching element connected thereto.
In the LCD, a voltage is applied to the two electrodes to generate an electric field in the liquid crystal layer, and transmittance of light which passes through the liquid crystal layer is controlled by varying the strength of the electric field to thus obtain a desired degree of light transmittance. The degree of light transmittance may be nearly simultaneously controlled in the plurality of pixels to generate an image.
Touch screen panels are input devices for enabling a user to interact with a machine such as a computer by writing or drawing characters or figures using a finger or a pen on a screen in a contact manner. The interaction may also be by using a finger or pen to press an on-screen button or icon to instruct the computer to perform an action. LCDs including the touch screen panels can recognize whether the finger of the user or the touch pen contacts on the screen and can also obtain contact position information of the contact.
However, the LCD including the touch screen panel has problems in that the installation of the touch screen panel increases a unit cost, an additional process of attaching the touch screen panel on a liquid crystal panel assembly reduces production yield, luminance of the LCD deteriorates, and a thickness of the product increases.